chore: sync annotation UI, shortcuts, and misc updates

frontend/src/pages/ReviewPage.jsx

@@ -500,7 +500,7 @@ export default function ReviewPage({ batchId: rawBatchId, projectId, onProject }
                   ? `${pool.exemplars.filter((e) => e.positive).length} example(s), `
                     + `${pool.exemplars.filter((e) => !e.positive).length} negative — `
                     + 'tune the filters, then Apply'
-                  : 'Drag an example of this class · Shift-drag = not this'}
+                  : 'Drag or double-click an example · Shift-drag/click = not this'}
               </span>
             )}
           </div>